Problem: On a beautiful afternoon, Umaima rode her bicycle to a farm that sold baskets of watermelons for $6.78 each and baskets of oranges for $5.21 each. Umaima decided to buy a basket of watermelons and a basket of oranges. How much did Umaima need to pay for her produce?
Solution: To find the total amount Umaima needs to pay, we need to add the price of the watermelons and the price of the oranges. Price of watermelons + price of oranges = total price. ${6}$ ${7}$ ${8}$ ${5}$ ${2}$ ${1}$ ${+\vphantom{0}}$ ${9}$ ${9}$ ${1}$ ${1}$ Umaima needs to pay $11.99.